But "even considering the unparalleled freedom to create that has been given to users of Second Life, much of The Grid [the online world] remains lifeless and very much inert," write the authors of the Ecosystem Working Group Web site.

This group of about a dozen programmers is working to flesh out Second Life with non-player creatures that have lives of their own.

Over the past several months the project's primary playground has been a sandy beach plot called Terminus, where the team has created a stable ecosystem with a few species of virtual plants and animals.

There's only one other ecosystem in Second Life that rivals Terminus in complexity: an island called Svarga, where rain makes plants grow, bees pollinate the plants, and the plants can slowly evolve.

Although the island's creatures are beautifully drawn, the computer code behind its inhabitants is hidden, and visitors can't create new living things.

But the island inspired Corey Hart, a neuroscientist at Drexel University in Philadelphia, Pennsylvania, to create Terminus and the Ecosystem Working Group.

Hart, who goes as Lucifitias Neurocam in the game world, also created an open source computer language for the artificial life, which anyone is free to use and change.